JP2019081508A - Instrument panel beam and instrument panel beam junction body using the same - Google Patents

Abstract

To provide an aluminum alloy-made instrument panel beam excellent in junction adhesive properties against resin bracket and to provide an instrument panel beam junction body using the same.SOLUTION: The instrument panel beam is constituted of a pipe formed from aluminum alloy as a base material and includes a junction part for joining to a resin bracket. The junction part includes a surface layer formed from a porous oxide film whose thickness is 50 nm to 300 nm and surface hole diameter is 10 nm to 100 nm and has a surface unevenness with an arithmetic average roughness Ra of 10 μm to 200 μm when measurement is made in a circumferential direction of the pipe.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an instrument panel beam, in particular, an instrument panel beam made of an aluminum alloy excellent in bonding adhesion to a resin bracket, and an instrument panel beam assembly using the same.

  Generally, in a vehicle such as an automobile, an instrument panel (hereinafter, also simply referred to as an "instrument panel") is provided in the front of the vehicle interior with devices such as various meters, audio devices, and airbags installed. . A tubular instrument panel beam (also referred to as instrument panel beam, instrument panel reinforcement, cross car beam, and steering hanger beam) extending substantially in the vehicle width direction and connecting the left and right vehicle body panels inside the instrument panel. Is provided. The instrument panel beam joins brackets for mounting various members, and is assembled to a vehicle body as an instrument panel beam joint.

  Since the instrument panel beam assembly is an automobile component to which a steering, an air conditioner, an audio device, and the like are attached, a strength to support these devices, devices, and the like is required. On the other hand, in order to cope with the environmental problems that have become serious in recent years, weight reduction of automobile parts in consideration of improvement of fuel consumption of the automobile is required. In order to cope with such weight reduction, application of an instrument panel beam made of aluminum alloy is being studied. Further, in order to further reduce the weight, it has been considered to reduce the thickness of the instrument panel beam or to form the bracket from a resin such as plastic.

  In order to reduce the weight of the instrument panel beam assembly, resinification of the bracket is effective. In this case, it is possible to bond the resin bracket and the instrument panel beam by pressure bonding the resin bracket molded in advance to the heated instrument panel beam. However, the shape of the bracket is complicated. Therefore, in order to join the resin bracket to the instrument panel beam at low cost, injection molding is more preferable than compression molding.

  In addition, since a relatively heavy device such as a steering wheel is attached to the bracket, a portion where the bracket and the instrument panel beam are joined with respect to the length direction (vehicle width direction) of the instrument panel beam Loads of various parts act at right angles. That is, torque is generated. For this reason, even if torque is applied to a bracket, high joint adhesion which these do not separate is required. By the way, the instrument panel beam is formed using a tube whose cross section is circular or nearly circular in shape. Since the load acting in the longitudinal direction is linear, the instrument panel beam is relatively strong against the load in the longitudinal direction, but the torque acting in the circumferential direction tends to rotate on the curved surface in the circumferential direction. It is necessary to improve the bonding adhesion in the circumferential direction. Therefore, higher bond strength is required in the circumferential direction of the instrument panel beam. Further, in order to support the above-mentioned devices, devices and the like, the instrument panel beam is required to be made of metal from the viewpoint of mechanical strength. However, since bonding of the metal instrument panel beam and the resin bracket is bonding between different materials, there is a case where sufficient bonding adhesion can not be obtained as an instrument panel beam bonded body.

  Furthermore, under hot summer, the instrument panel in the car may be heated to a temperature close to 80 ° C., and the temperature difference between night and day will cause the instrument panel beam assembly to be repeatedly subjected to the stress associated with the thermal cycle. . In this case, since the coefficient of thermal expansion differs greatly between resin such as plastic and metal such as aluminum, a large thermal stress acts at the interface between the metal and resin constituting the joined body, and the metal and the resin are easily peeled off. For this reason, even if the outer surface of the instrument panel beam made of metal is simply roughened to form irregularities on the surface, and the resin anchor effect at the joint with the resin bracket is expected, such an effect is obtained. In the stage immediately after the production of the instrument panel beam assembly which is remarkable, although the bonding adhesion is sufficient, when the thermal cycle is repeated, the bonding adhesion may be gradually reduced.

  In view of such problems, Patent Document 1 discloses a cylindrical portion made of a metal material such as an aluminum alloy, a fixing hole communicating the inside and the outside, and an inner portion facing the fixing hole. There is disclosed an instrument panel reinforcement provided with a peripheral wall portion. In addition, Patent Document 1 discloses an instrument panel in which an anchor portion of a resin bracket is formed by infiltrating a resin material between a fixing hole and an inner circumferential wall portion, and the resin bracket and the instrument panel reinforcement are mechanically joined. An reinforcement structure is disclosed. However, in this structure, since it is necessary to form an inner peripheral wall portion for fixing the anchor portion of the resin bracket inside the instrument panel reinforcement, the processing of the instrument panel reinforcement is complicated and expensive. In addition, Patent Document 1 does not mention at all the surface roughness of instrumental reinforcement, and further, the bonding adhesion after a thermal cycle.

  In Patent Document 2, an oxide film is further formed by anodizing treatment on the surface of the roughened aluminum or aluminum alloy plate, and adhesion between the aluminum or aluminum alloy plate and a resin as an adhesive agent is obtained. An improved printed wiring board is disclosed. However, since the instrument panel beam assembly is required to have high bond adhesion in a relatively narrow bond area, the bond adhesion exhibited by the printed wiring board may be insufficient in some cases. Further, Patent Document 2 does not mention at all the bonding adhesion after cold thermal cycle and the application of automobile parts, and the resin is a molded body bonded and adhered to a substrate by heat and pressure curing, Due to the complexity of the shape of the brackets used in the instrument panel beam assembly, such heat and pressure curing techniques for resins are not suitable for the manufacture of an instrument panel beam assembly.

JP, 2017-0502439, A Unexamined-Japanese-Patent No. 5-191001

  An object of the present invention is to provide an aluminum alloy instrument panel beam excellent in bonding adhesion to a resin bracket and an instrument panel beam assembly using the same.

  An aspect of the present invention is an instrument panel beam formed using a tube made of an aluminum alloy as a base material and having a joint for joining to a resin bracket, wherein the joint has a thickness of 50 nm to 300 nm, An instrument having a surface layer comprising a porous oxide film having a surface pore diameter of 10 nm to 100 nm and having surface irregularities having an arithmetic average roughness Ra of 10 μm to 200 μm when measured along the circumferential direction of the tube It is a panel beam.

  An aspect of the present invention is an instrument panel beam assembly including the instrument panel beam and the resin bracket joined to the instrument panel beam.

  An aspect of the present invention is the injection molded body in which the resin bracket is formed on the surface of the joint portion of the instrument panel beam.

  According to the present invention, an instrument panel beam formed using a tube made of an aluminum alloy as a base material has a joint for joining to a fat bracket, and the joint has a thickness of 50 nm to 300 nm, It has a surface layer made of a porous oxide film having a surface pore diameter of 10 nm to 100 nm, and has surface irregularities having an arithmetic average roughness Ra of 10 μm to 200 μm when measured along the circumferential direction of the tube There is. When the arithmetic average roughness Ra of the portion having the porous oxide film of the instrument panel beam formed using the tube made of aluminum alloy as the base material is 10 μm to 200 μm, the resin bracket is sufficiently in the concave portion of the surface unevenness The surface pores of the oxide film formed on the surface asperities are fixed by the anchor effect. Therefore, it is possible to obtain an instrument panel beam excellent in bonding adhesion to a resin bracket, and an instrument panel beam assembly using the same. In addition, the resin bracket and the aluminum alloy instrument panel beam can be normally joined by low-cost injection molding.

FIG. 1 is a schematic view for explaining a circumferential direction C of an instrument panel beam according to the present invention.

  Hereinafter, embodiments of the present invention will be described. In addition, this invention is not limited to the following embodiment, It can implement in a various aspect in the range which does not deviate from the summary of this invention.

[Instrument panel beam]
The instrument panel beam (hereinafter, also simply referred to as "beam") according to the present invention is formed using a tube made of an aluminum alloy as a base material, and is joined to a resin bracket (hereinafter also simply referred to as "bracket"). For the joint. A commercially available aluminum alloy tube can be used as the aluminum alloy as the base material, but a plate-like aluminum alloy is formed into a circular cross section by roll forming, and both ends are welded, so-called A seam pipe may be formed. Moreover, the cross-sectional shape does not need to be circular, and may be an ellipse, a polygon or the like. In the present invention, “joint” means a portion of a beam on which surface irregularities and a surface layer comprising a porous oxide film are formed, which corresponds to the joint before both of them are formed. The portion of the beam that is formed is referred to as the "junction equivalent portion".

  The aluminum alloy is not particularly limited, and, for example, an aluminum-copper alloy (Al-Cu alloy), an aluminum-manganese alloy (Al-Mn alloy), an aluminum-silicon alloy (Al-Si) Alloy), aluminum-magnesium alloy (Al-Mg alloy), aluminum-magnesium-silicon alloy (Al-Mg-Si alloy), aluminum-zinc-magnesium alloy (Al-Zn-Mg alloy) Etc. can be used. From the viewpoint of giving higher strength, an Al-Mg-based alloy, an Al-Mg-Si-based alloy, and an Al-Zn-Mg-based alloy are preferable.

  As such aluminum alloys, for example, Al-Cu alloys of alloy numbers A2014, A2017, A2024, A2219 according to the standard of JIS H 4080, Al-Mn alloys of alloy numbers A 3003, A 3004, Al-Si alloys of alloy number A 4032. Alloy No. A5052, A5056, A5083, A5154, A5182, A5454, A5N01 Al-Mg-based alloy, Alloy No. A6061, A6063, Al-Mg-Si-based alloy A6N01, Alloy No. A7003, A7050, A7075, A7178, An Al-Zn-Mg-based alloy or the like of A7N01 can be used.

  The bracket has a mounting site for bonding with the beam and a mounting site for mounting with other components in the instrument panel. The brackets can be joined to the beam according to mounting to various parts, such as side brackets for mounting on left and right vehicle body panels, column brackets for mounting steering columns, post brackets for supporting on dash panels, etc. . The shape of the bracket is not particularly limited as long as the mounting site can be joined to the beam, and the shape is appropriately determined according to the condition in the instrument panel of the automobile to which the beam is applied, the shape of parts mounted on the bracket, etc. It can be designed. Moreover, the resin which comprises a bracket is although it does not specifically limit, For example, PP (polypropylene), PA (polyamide), PPS (polyphenylene sulfide), ABS (acrylonitrile butadiene styrene), PC (polycarbonate), Examples thereof include PBT (polybutylene terephthalate) and the like and blend resins thereof, and from the viewpoint of the strength of the bracket, PA (polyamide) and PPS (polyphenylene sulfide) are preferable. In order to improve the strength, rigidity and impact resistance of these resins, it is also effective to use glass fiber, carbon fiber or the like or resin to which an elastomer is added.

  The joint equivalent portion is preferably formed on the outer peripheral surface of the base in order to form surface irregularities on a tube (hereinafter, also referred to as a “base”) made of an aluminum alloy which is a base of the beam. The joint equivalent portion may be the entire outer peripheral surface or a part of the outer peripheral surface. The joint equivalent portion corresponds to a position where the mounting portion of the bracket is joined to the outer peripheral surface of the beam. Also, a plurality of brackets may be joined to the outer peripheral surface of the beam, and can be appropriately designed according to the parts to which the brackets are attached, such as the center and the end of the beam in the longitudinal direction (vehicle width direction). The area of the joint equivalent portion is also not particularly limited, and can be appropriately designed according to the strength required for each bracket.

  In addition, surface irregularities having an arithmetic average roughness Ra of 10 μm to 200 μm, preferably 50 μm to 150 μm, are formed on the joint equivalent portion when measured along the circumferential direction of the substrate. The oxide film to be applied to the portion corresponding to the bonding portion is formed with a substantially uniform thickness on the surface asperity. That is, the resin as the bracket can improve adhesion by the large anchor effect by the surface unevenness and the small anchor effect by the hole of the oxide film applied to the portion corresponding to the joint portion. When the arithmetic average roughness Ra is less than 10 μm, sufficient bonding adhesion can not be obtained. On the other hand, when the arithmetic average roughness Ra exceeds 200 μm, the resin leaks at the time of injection molding of the bracket and normal injection molding can not be performed. . By forming a surface asperity with a relatively large surface roughness Ra in the joint equivalent portion, the actual bonding area between the bracket and the beam in the apparent area becomes large, and the resin constituting the bracket becomes surface asperity by injection molding The joint adhesion to the bracket is increased because it penetrates deeper into the recess of the. Therefore, it is important not only to roughen the surface of the substrate but also to allow the resin to enter the recess to a sufficient depth. Therefore, by forming surface irregularities having the surface roughness Ra within the above range on the outer surface of the substrate, bonding adhesion to the bracket is increased, and a beam having high bonding adhesion to the bracket can be obtained.

  On the other hand, due to the influence of torque in the instrument panel, the bracket may be broken and peeled off from the instrument panel beam. In particular, although the instrument panel beam is relatively strong against the load acting in the longitudinal direction, it can not sufficiently cope with the torque load acting in the circumferential direction, and the part where the bracket and the instrument panel beam are joined is Peeling is likely to cause unintended rotational movement of the bracket relative to the instrument panel beam. Therefore, it is necessary to further improve the bonding adhesion with the bracket at the torque in the circumferential direction of the instrument panel beam. In addition, the joint adhesion of the part where the bracket and the instrument panel beam are joined is at least the extent that the bracket does not rotate or break relative to the instrument panel beam when torque is applied to the bracket It is required to have the adhesion of

  Here, the arithmetic mean roughness Ra in the circumferential direction is, along the circumferential direction C, perpendicular to the longitudinal direction L parallel to the central axis X of the instrument panel beam 1, as shown in FIG. It means the surface roughness of the outer peripheral surface of the measured beam. Arithmetic mean roughness Ra is the surface roughness obtained by measuring the surface shape of the sample surface with a surface roughness measuring instrument etc. Specifically, the degree of micro unevenness formed on the outer peripheral surface of the beam Is quantified. For example, the beam according to the present invention can be used to measure the arithmetic mean roughness Ra in the circumferential direction of the beam using a surface roughness meter, a shape measuring machine, a laser microscope or the like. When the beam cross-sectional shape is not a straight line, it is desirable to measure with a shape measuring machine.

  Further, in the beam according to the present invention, the bonding portion is made of a porous oxide film having a thickness of 50 nm to 300 nm, preferably 100 nm to 200 nm, and a surface pore diameter of 10 nm to 100 nm, preferably 15 nm to 50 nm. It has a surface. If the thickness is less than 50 nm, the depth at which the resin penetrates into the surface pores of the oxide film is insufficient, and sufficient bonding adhesion can not be obtained. On the other hand, when the thickness exceeds 300 nm, not only long-time electrolytic treatment is required to thicken the thickness of the oxide film, but also when the temperature changes, the influence of the difference in thermal expansion coefficient between aluminum and resin It is large, and the decrease in bonding adhesion accompanying the thermal cycle is large. In addition, when the surface pore diameter of the oxide film is less than 10 nm, the resin hardly penetrates into the pores, and sufficient bonding adhesion can not be obtained. On the other hand, when the surface pore diameter exceeds 100 nm, when the temperature changes, the amount of expansion and contraction of the resin in the pores becomes relatively large, and the decrease in bonding adhesion accompanying the cooling and heating cycle becomes large.

  As described above, since the bonding portion has a surface layer made of a porous oxide film having a surface asperity with a sufficiently large surface roughness Ra and having a specific thickness and a specific surface pore diameter, The resin penetrates into the surface holes, and sufficient bonding adhesion can be obtained for bonding with the bracket. That is, the deformation of the resin due to the temperature change is also large in the joined resin blankets, as long as relatively rough surface irregularities having an arithmetic average roughness Ra of 10 μm to 200 μm as the surface roughness are formed on the outer surface of the substrate. Therefore, due to the repeated deformation of the resin accompanying the cooling and heating cycle, a gap is gradually formed between the concave portion of the surface asperity and the resin, and the bonding adhesion is significantly reduced. On the other hand, in the resin having a surface pore diameter in the range of 10 nm to 100 nm, deformation of the resin due to temperature change is also small. Therefore, even if the thermal cycle is repeated, almost no gap is formed, and the bonding adhesion is hardly reduced. Therefore, the bracket has a surface layer made of a porous oxide film having a surface roughness Ra in which the surface roughness Ra is in the above range, and having a thickness and a surface pore diameter in the above range. On the other hand, it is possible to obtain a beam which has high bonding adhesion and in which the decrease in bonding adhesion with respect to the thermal cycle is suppressed.

[Instrument panel beam assembly]
An instrument panel beam assembly according to the present invention (hereinafter, also simply referred to as a "bonded body") is composed of the beam and the resin bracket joined to the beam. Therefore, since the obtained bonded body also includes the above-described beam, it has excellent bonding adhesion to the bracket. Further, in the process of manufacturing the joined body according to the present invention, since the resin to be the bracket can be normally joined to the surface of the beam having the oxide film, that is, the joint by injection molding, It is also possible. Therefore, in the bonded body according to the present invention, preferably, the bracket bonded to the beam is an injection molded body formed on the surface of the bonded portion of the beam.

[Method of manufacturing beam and junction]
Next, a method of manufacturing a beam and a junction according to the present invention will be described by specifically illustrating the following.

(Manufacturing of beam)
First, a tube made of an aluminum alloy to be a base material of a beam according to the present invention is prepared. Next, the surface of the joint portion of the pipe is roughened to form a surface asperity having a predetermined surface roughness at the joint portion. The means for roughening is not particularly limited. For example, even when roughening is performed by mechanical polishing using an abrasive paper, a polishing tool, a polishing machine, etc., non-mechanical processing such as chemical polishing, electropolishing, etc. The surface may be roughened by a conventional polishing. Although polishing is used for the sake of convenience, it is not necessary to be particularly polishing, as long as surface irregularities having a predetermined surface roughness can be formed on the surface of the substrate. Further, the surface of the roughened substrate is subjected to anodizing treatment to form a surface layer made of a porous oxide film having a predetermined thickness and a predetermined surface pore diameter. Although the method and conditions of the anodizing treatment are not particularly limited, for example, a substrate having predetermined surface irregularities formed in an electrolyte such as sulfuric acid, oxalic acid, phosphoric acid, and other organic acids is added, and then , Or direct current, alternating current, or the like. Thereby, the beam according to the present invention can be manufactured.

(Manufacture of bonded body)
The bracket is injection-molded to the beam according to the present invention obtained as described above, and the bracket is joined to the joint of the beam. The method and conditions of injection molding are not particularly limited. For example, using an injection molding machine, the resin to be the material of the bracket is melted in a cylinder and then the molten resin corresponds to the shape of the bracket The resin can be injected into the mold, solidified in the mold by holding pressure, and cooled, and then the mold can be taken out. Thus, the bonded body according to the present invention can be manufactured.

  The present invention will be described in more detail based on the following examples, but the present invention is not limited to these examples.

[Examples 1 to 9 and Comparative Examples 1 to 6]
Each test piece was produced by the following manufacturing method, and the following evaluation was performed. The results are shown in Table 2.

(1) Production of instrument panel beam The surface corresponding to the joint equivalent portion of a tube made of an aluminum alloy made of an aluminum alloy of material (alloy number) A5052, outer diameter 40 mm, thickness 4 mm, length 150 mm is shown in Table 1 The surface was roughened with the abrasive paper (abrasive paper, sandpaper, etc.) to form surface irregularities having various surface roughness (arithmetic mean roughness Ra) at the joint portion. Then, a tube made of a roughened aluminum alloy was placed in an electrolytic solution (2% sodium pyrophosphate bath), and anodized by passing a 50 Hz sine wave alternating current as an anode. Thus, an instrument panel beam having a surface layer formed of an oxide film having various film thicknesses and surface pore diameters was manufactured.

  The surface roughness is an arithmetic mean roughness in the range of the length of 10 mm of the outer peripheral surface along the circumferential direction C of the instrument panel beam as shown in FIG. 1 using a Mitutoyo C-3000 profilometer. Ra was measured.

(Surface roughness measurement conditions)
The following settings were made in the calculation dialog box of the control software of the measuring machine.
Definition: Revised, Cutoff value: Default value (evaluation length), Correction: None, MR slice level: 10%,
Profile: R, Filter: Gaussian, Sm Count Level: 10%

(2) Production of instrument panel beam assembly Various resin brackets shown in Table 1 (joined portion: width 30 mm × peripheral length 63 mm, brackets: width 30 mm × high) for each instrument panel beam manufactured by the above method A 30 mm × 100 mm length was injection molded to produce an instrument panel beam assembly. Injection molding used a thermoplastic resin injection molding machine (J85AD-110H manufactured by Japan Steel Works, Ltd.) having a maximum mold clamping force of 85 t and a maximum injection amount of 110 ml.

(Injection molding conditions)
Resins constituting the bracket are four types of PP (polypropylene), PPS (polyphenylene sulfide, glass fiber 30%), PA 610 (polyamide 610), and ABS (acrylonitrile (A) -butadiene (B) -styrene (S)) They were selected and injection molded under the conditions shown in Table 1 below. In addition, since PP does not absorb water, drying of the resin is not implemented.

(3) Evaluation method (3-1) Injection molding situation When injection molding was performed on the above-mentioned conditions, the molding situation of the resin-made bracket was judged visually. The determination results are as follows.
○: Almost no burrs Normal ×: Large burrs are generated and can not be used as instrument panel beams

(3-2) Bonding adhesion evaluation (initial stage)
A steel pipe with an inner diameter of 41 mm was covered with an instrument panel beam to which a resin bracket was joined, compressed at a speed of 10 mm / min with a universal testing machine, and shear stress (MPa) when the resin bracket was broken was measured. . The determination results of the initial bonding adhesion are as follows. In the case of “◎” and “〇”, it is evaluated that high bonding adhesion is obtained in bonding of the resin bracket and the instrument panel beam, and in the case of “x”, sufficient bonding adhesion is obtained It was not evaluated.
:: Shear stress 30 MPa or more ○: Shear stress 20 MPa or more, less than 30 MPa ×: Shear stress less than 20 MPa

(After a thermal cycle test)
After 100 cycles of 30 minutes at 0 ° C and 30 minutes at 100 ° C with an instrument panel beam bonded with a resin bracket using a thermal cycle tester, it is the same as the measurement of initial bonding adhesion. The shear stress (MPa) was measured. The difference between the initial shear stress and the shear stress after the cooling cycle test (shear stress difference) was determined. The determination results of the bonding adhesion after the cooling cycle test are as follows. In the case of "o", it evaluated that the fall of the joint adhesiveness with respect to a thermal cycle was suppressed, and, in the case of "x", it evaluated that the fall of the joint adhesiveness with respect to a thermal cycle was not suppressed.
○: Shear stress difference is 5 MPa or less ×: Shear stress difference is greater than 5 MPa

  All of the test pieces of Examples 1 to 9 can be injection molded normally, and since the initial shear stress is all 20 MPa or more, high bonding is possible even in bonding of a resin bracket and an instrument panel beam. Adhesion was obtained. Furthermore, since the shear stress differences after the thermal cycle test are all 5 MPa or less, the decrease in bonding adhesion to the thermal cycle was also suppressed.

  Since the test piece of Comparative Example 1 has an arithmetic average roughness Ra of less than 10 μm and insufficient surface roughening, sufficient bonding adhesion can not be obtained. On the other hand, in the test piece of Comparative Example 2, the arithmetic average roughness Ra is larger than 200 μm, and roughening is performed excessively, and a large groove is present on the surface of the instrument panel beam, and the resin leaks during injection molding. It has gone. Therefore, normal injection molding could not be performed.

  In the test piece of Comparative Example 3, the thickness of the oxide film was less than 50 nm, the depth at which the resin penetrated into the surface pores of the oxide film was insufficient, and sufficient bonding adhesion was not obtained. On the other hand, the test piece of Comparative Example 4 has a thickness of more than 300 nm, and when the temperature changes, the difference in thermal expansion coefficient between aluminum and resin is large, and the bonding adhesion largely decreases with respect to the thermal cycle. The

  In the test piece of Comparative Example 5, the surface pore diameter of the oxide film was less than 10 nm, the resin did not easily penetrate into the surface holes of the oxide film, and sufficient bonding adhesion was not obtained. On the other hand, in the test piece of Comparative Example 6, the surface pore diameter exceeds 100 nm, and when the temperature changes, the amount of expansion and contraction of the resin in the hole becomes relatively large, so the bonding adhesion to the thermal cycle decreases. It was great.

  According to the present invention, an aluminum alloy instrument panel beam and an instrument panel beam assembly using the same according to the present invention have high bonding adhesion to a resin bracket and suppressed deterioration in bonding adhesion to a thermal cycle. It became possible to provide. INDUSTRIAL APPLICABILITY The instrument panel beam and the instrument panel beam assembly using the same according to the present invention can be used in an instrument panel of a car, and even in the hot summer sun, the bonding contact between the resin bracket and the instrument panel beam Since it is possible to suppress the decrease in sex, it is possible to expect improvement in reliability.

1 Instrument panel beam C circumferential direction L longitudinal direction X central axis

Claims (3)

An instrument panel beam formed of an aluminum alloy tube as a base material and having a joint for joining to a resin bracket,
The joint is
It has a surface layer consisting of a porous oxide film with a thickness of 50 nm to 300 nm and a surface pore diameter of 10 nm to 100 nm, and an arithmetic average roughness Ra of 10 μm to 200 μm when measured along the circumferential direction of the tube. An instrument panel beam characterized by having a certain surface asperity.   An instrument panel beam assembly comprising the instrument panel beam according to claim 1 and the resin bracket joined to the instrument panel beam.   The instrument panel beam assembly according to claim 2, wherein the resin bracket is an injection-molded body formed on a surface of a joint portion of the instrument panel beam.

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